Using ClassLoader to load and create instance of class

ClassLoaderDemo.java
class A implements Runnable{
    public void run(){
        for(int i=0;i<10;i++){
            try{Thread.sleep(500);}catch(Exception e){}
            System.out.println(i+"  A");
        }
    }
}
class ThreadDemo1 {
    public static void main(String ar[])throws Exception{

        A a1;
        Class c=Class.forName("A");
        a1=(A)c.newInstance();
        Thread t1=new Thread(a1);
        t1.start();
        System.out.println("Finished");
    }
}